Glulam vs CLT vs Solid Timber: A Technical Comparison for B2B Partners
Why Timber Dealers Need to Understand Glulam, CLT, and Solid Log Construction
The European timber construction market is expanding rapidly. Engineered wood products now account for a growing share of new-build and renovation projects across residential, commercial, and institutional sectors. For B2B dealers and distributors, understanding the technical differences between glulam (glue-laminated timber), CLT (cross-laminated timber), and solid log construction is no longer optional — it is a commercial necessity.
Each construction method serves different market segments, carries different margin profiles, and demands different levels of technical knowledge from dealer partners. Making the wrong recommendation to a project specifier or end customer can result in lost contracts, returns, and reputational damage. Making the right one opens doors to repeat business and referral networks.
This guide provides a detailed technical comparison of all three methods, written specifically for B2B dealers and distributors evaluating their product portfolio. It covers structural performance, thermal properties, applications, manufacturing processes, and business considerations that directly affect dealer profitability.
What Is Each Material?
Glulam (Glue-Laminated Timber)
Glulam is an engineered timber product manufactured by bonding multiple layers of dimensioned timber — typically Nordic spruce — with structural adhesive. All laminations run parallel to the grain direction, creating beams, columns, and wall elements with predictable and consistent mechanical properties.
The lamination process eliminates the natural defects found in single-piece timber. Knots, checks, and grain deviations are distributed across multiple layers rather than concentrated in a single cross-section. This makes glulam homes and structures significantly more reliable under load than their solid timber equivalents.
Glulam elements are manufactured to precise tolerances using CNC machinery, enabling complex architectural geometries including curved beams, tapered sections, and portal frames. Wall thicknesses for residential applications typically range from 88 mm to 220 mm, with lamination thicknesses of 40 mm to 45 mm per layer.
CLT (Cross-Laminated Timber)
Cross-laminated timber consists of multiple layers of timber boards bonded together at alternating 90-degree angles. This cross-lamination creates a rigid panel system with structural capacity in two directions, making CLT fundamentally different from glulam in both behaviour and application.
CLT panels function as both wall and floor elements, with typical thicknesses ranging from 60 mm to 300 mm depending on structural requirements. The bidirectional strength allows CLT to carry loads as a diaphragm, making it well-suited to multi-storey construction where it competes directly with steel and concrete framing systems.
CLT construction is panel-based rather than element-based. Entire wall and floor sections arrive on site as pre-cut panels, enabling rapid on-site assembly. Buildings of four to eight storeys are now routinely constructed in CLT across Scandinavia, Austria, and the United Kingdom. Projects exceeding 15 storeys have been completed in Norway and Australia.
Solid Log (Traditional Timber Construction)
Solid log construction uses single-piece machined logs, typically profiled with tongue-and-groove or double tongue-and-groove interlocking systems. Logs are stacked horizontally to form walls, with corner joints providing structural integrity through mechanical interlocking rather than adhesive bonding.
This is the oldest form of timber construction in northern Europe, and it remains commercially relevant for specific market segments. Modern solid log buildings use kiln-dried timber machined to precise profiles, delivering much tighter tolerances than traditional hand-hewn construction.
Solid log offers natural thermal mass, with the timber itself absorbing and releasing heat over a 24-hour cycle. Wall thicknesses for residential applications typically range from 44 mm for garden buildings to 134 mm or more for year-round habitation. Premium specifications use double-wall (twin-skin) construction with insulated cavities to achieve modern U-value requirements.
Technical Comparison Table
| Parameter | Glulam | CLT | Solid Log |
|---|---|---|---|
| Structural Strength | GL24h to GL32h (EN 14080) | C24 panels (EN 16351) | C16 to C24 (EN 14081) |
| Dimensional Stability | High — 12% MC, minimal movement | High — cross-layers resist movement | Moderate — 15-20% MC, settling expected |
| Thermal Performance (wall only) | U-value 0.15-0.25 W/m³K (with insulation) | U-value 0.15-0.20 W/m³K (with insulation) | U-value 0.20-0.50 W/m³K (thickness dependent) |
| Fire Resistance | Predictable charring rate (0.7 mm/min) | Predictable charring rate, mass timber advantage | Good mass timber performance, char layer protects core |
| Moisture Management | Factory-controlled MC 12 ± 2% | Factory-controlled MC 12 ± 2% | Kiln-dried to 15-18%, requires ongoing management |
| Typical Wall Thickness | 88 mm – 220 mm | 60 mm – 300 mm | 44 mm – 134 mm (single) / 200 mm+ (twin-skin) |
| Maximum Span | 30 m+ (beams and arches) | 12 m (standard panels) | 6-8 m (limited by log length) |
| Typical Applications | Premium residential, commercial, architectural | Multi-storey residential, institutional, modular | Garden buildings, holiday cabins, traditional residential |
| Lead Time (typical) | 6 – 10 weeks | 8 – 14 weeks | 4 – 6 weeks |
| Transport Complexity | Moderate — element-based loading | High — large panel transport, crane required | Low — flat-pack, standard container shipping |
| Customisation Flexibility | High — CNC-machined to specification | Moderate — panel geometry constraints | High — adaptable profiles and floor plans |
Structural Performance
Structural performance is the primary differentiator between these three construction methods, and it determines which project types each material can serve.
Glulam delivers the highest load-bearing capacity of the three options on a per-element basis. Glulam beams can span distances exceeding 30 metres without intermediate support, making them suitable for commercial buildings, sports halls, and open-plan residential designs. The parallel grain orientation concentrates strength along the beam axis, and the lamination process allows manufacturers to place higher-grade timber in the tension zones where it is needed most. Strength classes range from GL24h to GL32h under EN 14080, with characteristic bending strengths of 24 to 32 N/mm³.
CLT panels provide structural capacity in two directions due to their cross-laminated layup. This bidirectional strength is critical for wall and floor diaphragms in multi-storey buildings, where lateral loads from wind and seismic forces must be transferred through the structure. CLT panels typically achieve C24 strength grading under EN 16351. While individual panel spans are limited to approximately 12 metres, the system-level performance of CLT buildings is exceptional — particularly for structures of four storeys and above.
Solid log construction relies on the compressive strength of stacked horizontal members. Structural capacity is limited by natural timber dimensions and the connection details at corner joints and openings. Maximum practical spans without intermediate support are typically 6 to 8 metres. Solid log is graded to C16 or C24 under EN 14081. For dealer partners, this means solid log is most competitive in single-storey and two-storey residential applications where extreme spans are not required.
Dimensional stability also varies significantly. Glulam and CLT maintain moisture content at approximately 12%, resulting in minimal post-installation movement. Solid log at 15-20% moisture content will undergo settling of 30 to 50 mm per metre of wall height during the first 12 to 24 months. This settling must be accounted for in design detailing around windows, doors, and service penetrations.
Thermal and Energy Performance
Thermal performance determines which construction method is appropriate for year-round habitation and how each complies with national building regulations.
U-values are the standard metric for comparing wall thermal performance. Lower values indicate better insulation. Glulam wall systems with integrated insulation achieve U-values of 0.15 to 0.25 W/m³K, meeting or exceeding the requirements of most European building codes. CLT panels with external insulation systems achieve similar values of 0.15 to 0.20 W/m³K. Solid log walls without additional insulation range from 0.20 W/m³K (twin-skin with insulated cavity) to 0.50 W/m³K (single-wall 90 mm log), with thicker wall profiles and twin-skin configurations narrowing the gap.
Thermal mass is an area where solid log has a genuine advantage. The mass of timber in a solid log wall absorbs heat during the day and releases it at night, moderating internal temperature swings. This thermal flywheel effect is measured by thermal diffusivity rather than U-value alone, and it means that solid log buildings can perform better in practice than their U-value might suggest — particularly in climates with significant day-night temperature variation.
For insulation integration, glulam and CLT both accept standard insulation materials (mineral wool, wood fibre, rigid PIR boards) within or external to the primary structural element. Solid log buildings in twin-skin configuration incorporate insulation between the two log walls. Single-wall solid log buildings can be internally or externally insulated, though this obscures the timber aesthetic that is often the primary selling point.
For dealer partners selling into markets with strict energy performance requirements (such as the United Kingdom, Germany, or Scandinavia), glulam and insulated solid log twin-skin systems are the most straightforward routes to compliance without compromising the timber character of the building.
Applications and Market Positioning
Each construction method occupies a distinct position in the market, and understanding these positions helps dealers target the right customers with the right products.
Glulam serves the premium residential and commercial segments. Architecturally designed homes, bespoke structures with large glazing areas, and commercial buildings with open-span requirements are the natural territory for glulam construction. The material carries a premium positioning that supports higher margins for dealers who can demonstrate technical competence to project specifiers. Glulam houses represent a growing segment across Europe, with particular strength in the Nordic countries, Germany, and the United Kingdom.
CLT is positioned in the mid-rise and commercial construction market, where it competes with steel frame and reinforced concrete rather than with other timber systems. The typical CLT customer is a construction company or developer building apartment blocks, schools, offices, or mixed-use developments. CLT projects tend to be higher value but lower volume for dealers, and they require engineering-level technical support throughout the sales and specification process.
Solid log covers the broadest market range, from compact garden buildings and home offices through to traditional residential cabins and holiday accommodation. The lower entry point and faster delivery times make solid log the highest-volume product category for most timber dealers. Log cabins are established in consumer awareness and require less technical selling than engineered timber alternatives. For dealers building their timber business, solid log is typically the foundation product line upon which glulam and other ranges can be added over time.
Portfolio diversification across both glulam and solid log allows dealers to serve projects at multiple price points and complexity levels, reducing dependency on any single market segment.
Manufacturing and Supply Chain
Manufacturing processes differ significantly between the three methods, and these differences directly affect lead times, logistics, and the level of factory customisation available to dealers.
Glulam manufacturing begins with timber grading and moisture conditioning. Laminations are planed, finger-jointed to length, and bonded under pressure with structural adhesive. The assembled billets are then machined to their final profile using CNC equipment. At UAB Eurodita, glulam production uses Hundegger CNC machinery (Germany) to achieve the precision required for complex joint geometries and custom profiles. Nardi kilns (Italy) ensure consistent moisture content throughout the raw material. Typical lead time for bespoke glulam structures is 6 to 10 weeks from confirmed order, depending on complexity and current production scheduling.
CLT manufacturing is a high-capital process requiring panel presses capable of handling panels up to 16 metres in length and 3 metres in width. The cross-lamination bonding process uses either structural adhesive or mechanical fixings (dowels or nails). CLT manufacturing is concentrated among a relatively small number of large-scale producers, primarily in Austria, Germany, and Scandinavia. Lead times of 8 to 14 weeks are typical, and minimum order quantities are generally higher than for glulam or solid log.
Solid log manufacturing involves log profiling (creating the tongue-and-groove or double-groove interlocking profile), CNC machining for corner joints and openings, and bundling for flat-pack transport. This process is well established and efficient, with lead times of 4 to 6 weeks for standard and semi-custom designs. Solid log is the most transport-efficient of the three methods, as flat-packed log kits fit standard shipping containers with high packing density.
It is important for dealer partners to note that Eurodita manufactures both glulam and solid log construction. CLT is a separate product category manufactured by specialist CLT producers. Dealers seeking to offer all three methods will need separate supply relationships for CLT, whereas glulam and solid log can be sourced from a single manufacturing partner.
Dealer Margin and Business Considerations
Margin potential varies across the three construction methods, driven by differences in product value, competitive intensity, and customer expectations.
Glulam projects typically offer the highest margin percentages for dealers. The premium positioning, technical complexity, and lower competitive intensity in this segment support stronger pricing. However, sales cycles are longer, and dealers must invest in technical knowledge and specification support. Glulam customers expect detailed engineering documentation, 3D visualisations, and responsive technical support throughout the project lifecycle.
CLT projects carry high absolute values but can involve margin compression due to competitive tendering processes in the commercial construction sector. The technical support requirements are substantial, and dealers must be prepared to engage with structural engineers, architects, and main contractors. The repeat business potential is strong with construction companies that standardise on CLT for their project pipeline.
Solid log products generate the highest volume for most dealers, with shorter sales cycles and a broader customer base. Margins per unit are typically lower than glulam, but the higher transaction volume and lower technical support burden produce competitive total margin contribution. After-sales requirements are manageable with proper customer guidance on maintenance, staining, and settling adjustment. Repeat and referral business is common in the garden building and holiday cabin segments.
For dealers evaluating portfolio strategy, a combination of glulam (premium, higher-margin) and solid log (volume, market breadth) provides the most resilient business model. This dual approach is achievable through a single manufacturing relationship, reducing supply chain complexity and improving commercial terms through consolidated volume.
Which Construction Method Should You Offer?
The optimal product mix depends on your market position, customer base, and growth objectives. The following framework can help guide the decision.
If your market is primarily garden buildings and small structures: Solid log should be your core product line. It offers the fastest turns, the lowest capital requirement per transaction, and the broadest addressable market. Consider adding glulam garden offices and studios as a premium upsell option.
If your market includes residential and architectural projects: Glulam is essential. The ability to offer residential-grade structures with premium finishes and bespoke floor plans differentiates your business from volume-only competitors. Solid log twin-skin builds serve the traditional residential segment alongside the glulam range.
If your market targets commercial and multi-storey development: CLT will be relevant, though it requires a separate supply chain and significantly deeper technical capabilities. Most dealers enter this segment after establishing their residential and light commercial business.
Eurodita operates as a single-source manufacturing partner for both glulam and solid log construction, with production capacity of approximately 150,000 m³ of Nordic spruce annually. This enables dealers to consolidate their supply chain while offering a technically diverse product portfolio. For more detail on the technical specifications of each method, consult the detailed product documentation or contact the partner management team directly.
Frequently Asked Questions
Is glulam stronger than solid timber?
Yes. Glulam achieves higher and more consistent strength grades than equivalent solid timber sections. A GL24h glulam beam has a characteristic bending strength of 24 N/mm³, compared to 16 N/mm³ for C16 solid timber. The lamination process distributes natural defects and allows optimised timber placement, eliminating the weak-point variability inherent in single-piece timber.
What is the typical lead time for glulam houses?
Standard glulam house kits are typically manufactured within 6 to 10 weeks from confirmed order, depending on project complexity and current production scheduling. Highly bespoke designs with non-standard geometries may require additional engineering time before production commences. Solid log alternatives offer shorter lead times of 4 to 6 weeks for comparison.
Can dealers offer both glulam and solid log from the same manufacturer?
Yes. Manufacturers with both production capabilities, such as UAB Eurodita, enable dealers to source glulam and solid log product ranges through a single supply relationship. This consolidation reduces procurement complexity, improves commercial terms, and provides a single point of technical support for both product lines.
What wall thickness options are available for glulam?
Glulam wall elements are available in thicknesses ranging from 88 mm to 220 mm for residential applications. Each lamination layer is typically 40 mm to 45 mm thick. The appropriate wall thickness depends on structural requirements, thermal performance targets, and regional building regulation compliance. Thicker profiles accommodate integrated insulation for enhanced energy performance.
How does CLT compare to glulam for residential projects?
For single-storey and two-storey residential buildings, glulam is generally the more practical and cost-effective choice. CLT offers advantages in multi-storey construction (four storeys and above) where its panel-based system and bidirectional strength become structurally advantageous. For standard residential projects, glulam provides greater design flexibility, lower transport costs, and wider supplier availability.
Is solid log construction suitable for year-round living?
Yes, provided the specification is appropriate. Single-wall solid log construction with wall thicknesses below 90 mm is primarily suited to seasonal or occasional use. For year-round habitation, twin-skin (double-wall) construction with insulated cavity, or single walls of 134 mm and above with supplementary insulation, achieves the thermal performance required for permanent residential occupation in most European climates.
What certifications should dealers look for in timber suppliers?
Key certifications include CE marking under the relevant harmonised standard (EN 14080 for glulam, EN 14081 for solid timber, EN 16351 for CLT), FSC or PEFC chain-of-custody certification for sustainable sourcing, and ISO 9001 for quality management systems. Factory production control (FPC) certification is mandatory for CE-marked structural timber products and confirms ongoing compliance with manufacturing standards.
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